Material used in the construction of the M3 motorway in Co Meath was sourced from two quarries which also supplied material to houses later discovered to have problems of subsidence.
More then 400 homes in north County Dublin suffered from movement of foundations and up to 20,000 homes across the country have allegedly been damaged by pyrite, an infill material allegedly used in their construction.
But while chief executive of the National Roads Authority (NRA) Fred Barry acknowledged infill material for the M3 had been sourced from two quarries from which it was also alleged pyrite had been sourced, he dismissed any suggestion of serious damage to the motorway.
Mr Barry told Meath TD Shane McEntee there was no need for an independent audit of the M3 or the section of N3 from the West-link toll to Clonee.
Speaking at the Oireachtas Committee on Transport today Mr Barry said infill material for support structures such as cement pillars and steel bars was rigorously monitored and could be traced. The NRA was happy no material from the two quarries identified had been used in connection with either steel or cement.
He said the material from the quarries could only have been used in relation to embankments. In this regard, pyrite - if it had been present at all - was not boxed in by foundations as it would be in a house. There would be minimal impact if the material "shifted, heaved, or expanded" as it might in foundations.
Mr Barry said there was no recorded incidence of pyrite ever having definitively affected one of the National routes, although he did accept there was one recorded incidence of a motorway "heaving" by a few millimetres. It was not a serious problem he said, and had never been unquestionably attributed to pyrite.
However Mr McEntee said he did not accept there was no need for an independent audit of the presence of pyrite in the motorway and he questioned whether the contractor would be willing or able to rectify the matter if major issues developed in a number of years, as had happened with the houses.
Tommy Broughan of the Labour Party also questioned the NRA on the presence of pyrite commenting he had been first to estimate that there may be up to 20,000 affected homes which were not covered by their insurance policies. The cost of remedial action for the houses could be as much as €60 billion, he maintained.
